Contributors
Preface
Introduction. Variability: A Key to Understanding Plant-Herbivore Interactions
Text
References
Part I. Sources of Intraplant Variation and Consequences for Herbivores
1. Host Manipulation of Parasites: Within-Plant Variation as a Defense against Rapidly Evolving Pests
I. Introduction
II. Variation as a Plant Defense
III. Host Selection by Pemphigus Gall Aphids
IV. Between-Plant Variation in Resistance
V Within-Plant Variation in Resistance
VI. Impact of Within-Plant Variation on Parasites
VII. Discussion
VIII. Summary
References
2. Insect-Induced Chemical Signals Regulating Natural Plant Protection Responses
I. Introduction
II. Proteinase Inhibitors and Natural Plant Protection
III. Summary
References
3. Habitat Selection and Foraging Tactics of Caterpillars in Heterogeneous Trees
I. Introduction
II. Patterns of Feeding-Site Variation in Tree Canopies
III. The Impact of Variability on Defoliating Insects
IV Conclusions
References
4. Leaf Age as a Predictor of Herbivore Distribution and Abundance
I. Introduction
II. Temporal Variation in Leaf Quality
III. Temporal and Spatial Patterns of Herbivory
IV A Case Study of Within-Plant Variation and Its Effects on Herbivore Distribution
V Concluding Remarks
References
5. Competition between Herbivores and Increased Resource Heterogeneity
I. Introduction
II. Introduced Species: A Unique Encounter between Plant and Herbivore
III. Nutritional Requirements of Herbivorous Insects
IV Foliar Nitrogen: A Basis for Fitness in Elongate Hemlock Scale
V Quality and Availability of Food for Exotic Hemlock Scales
VI. Summary and Conclusions
References
6. Herbivore Population Dynamics and Plant Chemistry
I. Introduction
II. Effects of Stressful Environments on the Proximate Nutritional Quality of Plants
III. Theory of Plant Defense
IV Effect of Physical Stress on Plant Defenses
V. Defensive Responses of Plants to Herbivore Attack
VI. Offensive Adaptations of Herbivores for Discrimination between Suitable and Unsuitable Food and for Synchronizing Reproduction with the Availability of Suitable Food
VII. Offensive Adaptations of Herbivores that Stress, Increase the Nutritional Quality of, or Circumvent Induced Defensive Responses of Plants
VIII. Direct and Indirect Effects of Food-Plant Nutritional Quality and Defensive Posture on Fitness of Herbivores
IX. Changes in Herbivore Properties during Population Fluctuations
X. Possible Pheromonal Interactions among Plants and Herbivores
XI. Theory of Herbivore Outbreaks
XII. Conclusion
XIII. Summary
References
Part II. Sources of Interplant Variation and Consequences for Herbivores
7. Ecology of Host-Selection Behavior in Phytophagous Insects
I. Introduction
II. Habitat Selection
III. Discrimination between Host Species
IV. Conspecific Host Discrimination
V Conclusions
References
8. Influence of Vegetation Texture on Herbivore Populations: Resource Concentration and Herbivore Movement
I. Introduction
II. Testing the Resource-Concentration Hypothesis
III. Mechanisms that Underlie the Responses of Herbivores to Vegetation Texture
IV Questions of Scale and Some Issues in Experimental Design
V A Plea for a Theory of Herbivore Search
VI. Final Remarks
References
9. Tracking Variable Host Plants in Space and Time
I. Introduction
II. Natural History, Distribution, and Abundance of Prokelisia marginota
III. Wing Dimorphism in Prokelisia marginata, Mechanisms of Its Determination, and Correlates with Reproduction
IV Potential Competitors, Predators, and Parasites of Prokelisia marginata
V Distribution, Structure, and Growth Dynamics of Spartina alterniflora
VI. Food Items, Patches, and Habitats as Levels of Resource Organization
VII. Microhabitat Distribution of Planthoppers on Grass Rosettes and the Definition of Favorable Food Items
VIII. Within-Habitat Variation in the Favorableness of Spartina alterniflora: Differences in Patch Selection between Wing Forms
IX. Between-Habitat Variation in the Favorableness of Spartina alterniflora: Differences in Habitat Selection between Wing Forms
X. Geographic Differences in the Wing-Form Composition of Prokelisia marginata Populations
XI. Conclusions and General Considerations
References
10. Effects of Host-Plant Variability on the Fitness of Sedentary Herbivorous Insects
I. Introduction
II. Measuring the Effect of Adaptations on Fitness
III. Examples
IV Discussion
References
Part III. Host Plants and Genetic Variation in Herbivore Populations
11. Evolution of Feeding Specialization, Physiological Efficiency, and Host Races in Selected Papilionidae and Saturniidae
I. Introduction: The Feeding-Specialization Hypothesis
II. Conclusion
References
12. Adaptation, Host Specificity, and Gene Flow in the Black Pineleaf Scale
I. Introduction
II. Density Dependence
III. How Does Colonizing Ability Vary with Density?
IV Survivorship Patterns Affect the Scale Sex Ratio
V A Genetic Model of Adaptation and Specificity
VI. Discussion: Some Implications of Genetic Variation
References
13. An Evolutionary-Genetic View of Host-Plant Utilization by Insects
I. Introduction
II. Maintenance of Genetic Variation by Environmental Heterogeneity: Theory
III. Evidence
IV. Summary and Concluding Remarks
References
Part IV Host Variability and the Structure of Plant-Herbivore Communities
14. Individual, Population, and Geographic Patterns in Plant Defense
I. Introduction
II. Effects of Defoliation on Plant Fitness
III. Value of Leaf Tissue to the Plant
IV. Seasonal Change in Allocation to Growth, Defense, and Reproduction
V Patterns of Allocation in Plant Morphs, Cultivars, and Species
VI. Differences in Leaf Defense between Plant Populations
VII. Latitudinal, Altitudinal, and Island-Mainland Patterns in Plant Defense
VIII. Summary and Conclusion
References
15. Phytochemical Variation, Colonization, and Insect Communities: The Case of Bracken Fern (Pteridium aquilinum)
I. Introduction
II. Chemical Variation: Sources, Scales, and Impacts
III. Bracken Defense and the Insect Community: An Overview
IV Summary and Conclusion
References
16. Hypotheses on Organization and Evolution in Herbivorous Insect Communities
I. Introduction
II. The Evolution of Specialists
III. Hypotheses on Community Organization
IV Communities at Equilibrium or Nonequilibrium?
V The Role of Competition
VI. Vacant Niches in Ecological and Evolutionary Time
VII. Compound Communities
References
Part V Host Variability and Herbivore Pest Management
17. Genetics of Plant-Herbivore Systems: Interactions between Applied and Basic Study
I. Introduction
II. Current Procedures and Concepts in the Development and Deployment of Resistant Varieties
III. Theoretical Considerations
IV Available Data on the Genetics of Plant-Herbivore Interactions
V The Need for Future Interaction between Resistance Breeders and Evolutionary Biologists
References
18. Manipulation of Host Suitability for Herbivore Pest Management
I. Introduction
II. Manipulation of the Suitability of Individual Host Plants
III. Manipulation of the Spatial Variation in Host Suitability
IV Effects of Host-Plant Variation on the Parasitoids of Phytophagous Insects
V Conclusions and Directions for Further Research
References
Index